Dear Editor,

  Cancer-related craniofacial pain can severely affect a patient’s quality of life and is often difficult to control with regular analgesics. Intrathecal targeted drug delivery is a proven and accepted therapy in cancer patients for the treatment of uncontrolled refractory pain. The intrathecal catheter tip is generally placed near to the site of greatest pain. However, for craniofacial cancer pain, the catheter tip is usually placed far away from the root entry zone of the cranial nerves, which innervate head and face tissues, thus potentially leading to inadequate analgesia. Here, we describe a case of a terminal cancer patient with intractable pain who was successfully treated by intrathecal targeted drug delivery by placing the catheter tip near the prepontine cistern.

Case

A 65-year-old female patient with metastatic lung cancer with a lesion to the frontal part of the skull (Figure 1, A and B), presented with severe head pain, which was refractory to oral medications, including oxycodone sustained-release tablets 80mg bid and gabapentin 300 mg tid. The pain was rated 6-7 on the numeric rating scale(NRS) at rest and 9-10 of breakthrough pain, which occurred frequently. Following this, an intrathecal catheter with an external port was implanted. For the insertion of the intrathecal catheter, the patient was placed in a left lateral decubitus position. A lumbar puncture was made with a Tuohy needle at the L2-L3 interspace and an intrathecal catheter (ZS2 Implantable Access Port, Linhwa, China) was inserted in the subarachnoid space in the cranial direction under fluoroscopic guidance. The tip of the catheter was carefully placed within the prepontine cistern (Figure 1, C and D). The end of the catheter was then tunneled subcutaneously and connected to a subcutaneous port in the right upper abdomen. An external electronic pump was connected to the port using a butterfly needle. The patient was given an external pump containing 0.03 mg/ml morphine, with a bolus of 0.1-ml each time and a 30-min lockout interval. No respiratory depression, sedation, nor confusion occurred. The dose of intrathecal morphine was started at 0.03 mg morphine daily, and gradually titrated up for improved pain control. The NRS was rated 1-2 at rest and 5-6 at worst during breakthrough pain, which was improved with administration of one bolus. The frequency of breakthrough pain episodes was also decreased. The oral oxycodone sustained-release tablets were stopped 1 week later. In the third month of this treatment, the patient’s continuous infusion rate was adjusted to deliver morphine 0.08 mg/day. The severe pain in the frontal part of the head was greatly reduced and she was satisfied with the results of intrathecal analgesic therapy.